Papers by Amar Abderrahmani
FEBS letters, Jan 7, 2005
Silencing of the transcriptional repressor REST is required for terminal differentiation of neuro... more Silencing of the transcriptional repressor REST is required for terminal differentiation of neuronal and beta-cells. In this study, we hypothesized that REST expression is controlled by hairy and enhancer of split 1 (HES-1), a transcriptional repressor that plays an important role in brain and pancreas development. We identified several N elements (CTNGTG) within the promoter of REST and confirmed that HES-1 associates with the endogenous promoter of REST. Moreover, using a cells model that overexpress HES-1 and a combination of experimental approaches, we demonstrated that HES-1 reduces endogenous REST expression. Taken together, these results indicate that HES-1 is an upstream negative regulator of REST expression.
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Diabetes, 2008
RESULTS Ex-4 inhibited induction of the JNK pathway elicited by IL-1β. This effect was mimicked ... more RESULTS Ex-4 inhibited induction of the JNK pathway elicited by IL-1β. This effect was mimicked with the use of cAMP-raising agents isobutylmethylxanthine and forskolin and required activation of the protein kinase A. Inhibition of the JNK pathway by ex-4 or IBMX and forskolin was ...
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Diabetes
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... 13. Cheviet S, Waselle L, Regazzi R. Noc-king out exocrine and endocrine secretion. Trends Ce... more ... 13. Cheviet S, Waselle L, Regazzi R. Noc-king out exocrine and endocrine secretion. Trends Cell Biol 2004; 14(10):525-528. Page 10. 170 ... 82. Delia Fazia MA, Servillo G, Foulkes NS et al. Stress-induced expression of transcriptional repressor ICER in the adrenal gland. ...
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Cellular and Molecular Life Sciences
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Revue Francophone des Laboratoires
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Nanoscale
Drug loaded hydrogels have proven to be versatile controlled-release systems. We report here on h... more Drug loaded hydrogels have proven to be versatile controlled-release systems. We report here on heat active hydrogels’ formation by mixing graphene oxide (GO) or carboxyl enriched reduced graphene oxide (rGO-COOH)...
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Nature genetics, Jan 8, 2018
Study of monogenic forms of obesity has demonstrated the pivotal role of the central leptin-melan... more Study of monogenic forms of obesity has demonstrated the pivotal role of the central leptin-melanocortin pathway in controlling energy balance, appetite and body weight 1 . The majority of loss-of-function mutations (mostly recessive or co-dominant) have been identified in genes that are directly involved in leptin-melanocortin signaling. These genes, however, only explain obesity in <5% of cases, predominantly from outbred populations 2 . We previously showed that, in a consanguineous population in Pakistan, recessive mutations in known obesity-related genes explain ~30% of cases with severe obesity3-5. These data suggested that new monogenic forms of obesity could also be identified in this population. Here we identify and functionally characterize homozygous mutations in the ADCY3 gene encoding adenylate cyclase 3 in children with severe obesity from consanguineous Pakistani families, as well as compound heterozygous mutations in a severely obese child of European-American des...
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Diabetes & Metabolism
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Diabetes & Metabolism
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Molecular metabolism, Jun 1, 2017
Genome-wide association studies (GWAS) have identified >100 loci independently contributing to... more Genome-wide association studies (GWAS) have identified >100 loci independently contributing to type 2 diabetes (T2D) risk. However, translational implications for precision medicine and for the development of novel treatments have been disappointing, due to poor knowledge of how these loci impact T2D pathophysiology. Here, we aimed to measure the expression of genes located nearby T2D associated signals and to assess their effect on insulin secretion from pancreatic beta cells. The expression of 104 candidate T2D susceptibility genes was measured in a human multi-tissue panel, through PCR-free expression assay. The effects of the knockdown of beta-cell enriched genes were next investigated on insulin secretion from the human EndoC-βH1 beta-cell line. Finally, we performed RNA-sequencing (RNA-seq) so as to assess the pathways affected by the knockdown of the new genes impacting insulin secretion from EndoC-βH1, and we analyzed the expression of the new genes in mouse models with a...
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Journal of Controlled Release, 2016
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Journal of controlled release : official journal of the Controlled Release Society, Jan 30, 2016
The development of a skin-mounted patch capable of controlled transcutaneous delivery of therapeu... more The development of a skin-mounted patch capable of controlled transcutaneous delivery of therapeutics through thermal activation provides a unique solution for the controlled release of active principles over long-term periods. Here, we report on a flexible transdermal patch for photothermal triggered release of ondansetron (ODS), a commonly used drug for the treatment of chemotherapy-induced nausea and vomiting and used as model compound here. To achieve this, a dispersion of ODS-loaded reduced graphene oxide (rGO-ODS) nanosheets were deposited onto Kapton to produce a flexible polyimide-based patch. It is demonstrated that ODS loaded Kapton/rGO patches have a high drug delivery performance upon irradiation with a continuous laser beam at 980nm for 10min due to an induced photothermal heating effect. The ability of ODS impregnated Kapton/rGO patches as transdermal delivery scaffolds for ODS across the skin is in addition investigated using porcine ear skin as a model. We show that ...
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Molecular Metabolism, 2016
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Data Revues 12623636 V34ss3 S1262363608729057, Mar 16, 2010
ABSTRACT Introduction La contribution potentielle des taux élevés des particules de LDL-cholestér... more ABSTRACT Introduction La contribution potentielle des taux élevés des particules de LDL-cholestérol oxydés et des concentrations plasmatiques diminuées de HDL dans la progression du diabète a été récemment mise en évidence. L’exposition prolongée des cellules β pancréatiques humaines ou murines aux LDL-cholestérol oxydés provoque leur mort par apoptose. En revanche, les particules de HDL protègent les cellules de la mort induite par les lipoprotéines modifiées. L’objectif de cette étude fût de déterminer si la mort des cellules β induite par les LDL oxydés implique l’activation du stress du réticulum endoplasmique (stress ER), un processus connu pour induire l’apoptose des cellules β confrontées à l’hyperglycémie et l’hyperlipidémie chronique. Matériels et méthodes La lignée de cellules sécrétrices d’insuline de souris MIN6 a été incubée en présence de 2 mM LDL-cholestérol natifs ou oxydés, avec ou sans 1 mM de HDL, pendant 72 heures. Les marqueurs du stress du réticulum endoplasmique ont été quantifiés par PCR quantitative. Résultats L’exposition prolongée des cellules en présence des lipoprotéines oxydées entraîne une augmentation de 2-3 fois des niveaux de ATF4, p58 et CHOP. En revanche, les LDL natifs n’induisent pas de modification de l’expression de ces marqueurs. L’ajout de particules HDL dans le milieu de culture, bloque efficacement l’activation des marqueurs du stress réticulaire induite par les LDL oxydés. Conclusion Ces données montrent que les LDL oxydés engendrent leurs effets délétères en activant le stress ER et met en lumière la capacité des HDL-cholestérol à contrecarrer ces effets.
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Sensors and Actuators B: Chemical, 2016
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Data Revues 12623636 003500s1 22, Mar 1, 2009
ABSTRACT Introduction La protéine islet brain 1 (IB1) joue un rôle clé dans les effets prodigués ... more ABSTRACT Introduction La protéine islet brain 1 (IB1) joue un rôle clé dans les effets prodigués par le mimétique du glucagon-like peptide 1, l’exendin-4 (ex-4), sur la survie des cellules bêta et très certainement sur l’expression de l’insuline. Ce rôle est essentiellement lié au contrôle de la voie de signalisation c-Jun N-terminal kinase (JNK). En outre, IB1 contrôle la sécrétion de l’insuline de manière indépendante du métabolisme du glucose et de la voie de JNK. Ce mécanisme contribuerait aussi aux effets sécrétagogues du GLP-1 et de ces analogues mimétiques. L’objectif de ce travail fut de comprendre le mécanisme par lequel IB1 contrôle la sécrétion de l’insuline. Matériels et méthodes Des ARN interférant dirigés spécifiquement contre IB1 ont été introduits dans les cellules sécrétrices d’insuline de rat INS-1Evia un vecteur lentiviral. L’insuline contenue dans les cellules, et relâchée, est mesurée par EIA. Les protéines totales des cellules ont été sujettes à une analyse protéomique et au micro-séquencage. Résultats La suppression sélective d’IB1 entraîne une perte de sécrétion de l’insuline. Cette perte de fonction est associée avec un profil protéomique qui diffère de celui des cellules contrôles. L’annexine a2 (Anxa2) est une des protéines dont les niveaux s’effondrent dans les cellules où IB1 est diminuée. Anxa2 contrôle la sécrétion des cellules neuroendocrines, en réorganisant les filaments d’actine. La réduction de l’expression de l’Anxa2 par ARN interférence mime les effets de la suppression d’IB1 sur la sécrétion de l’insuline. Conclusion IB1 contrôle la sécrétion de l’insuline en maintenant les niveaux de l’Anxa2.
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Diabetes Metab, 2011
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Mol Cell Endocrinol, 2009
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Diabetes & Metabolism, 2009
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Papers by Amar Abderrahmani